Computer controlled manufacturing systems, such as “3-D printers,” laser cutter/engravers, CNC milling machines, and the like, can be used to create complicated items where traditional manufacturing techniques like moldings or manual assembly fail. Such automated methods operate based on instructions that specify the cuts, layers, patterns, and other actions to be performed. The instructions can be in the form of computer files transferred to the memory of a computer controller for the machine and interpreted at run-time to provide a series of steps in the manufacturing process.